1. Field of the Invention
The present invention relates to a multi-processor control device and method which control a plurality of processors.
2. Description of the Related Art
As a power consumption reduction technique for a program having a constraint, there has been proposed a technique of controlling a frequency/power supply voltage so as to execute the program by using as low frequency/power supply voltage as possible within the range in which the constraint is satisfied.
a conventional technique determines a frequency/power supply voltage on the basis of the profile information of a program.
According to another conventional technique, when the constraint of a program is not satisfied, control is performed by using information obtained at the time of execution of the program to increase the frequency/power supply voltage so as to satisfy the constraint. In contrast to this, when there is a margin in terms of performance, a frequency/power supply voltage is determined by feedback control such as decreasing the frequency/power supply voltage.
A reference 1 (Masaaki Kondo and Hiroshi Nakamura, “Proposal of Dynamic Power Supply Voltage/Frequency Control Technique for CMP”, IPSJ SIG Technical Reports, Vol. 2005, No. 56, published May 31, 2005, p. 25, Information Processing Society of Japan) has proposed a technique of improving fairness and achieving an improvement in performance and a reduction in power consumption or energy consumption by controlling the operating frequency and power supply voltage of each processor, instead of dividing a cache, using a dynamic power supply voltage/frequency control (DVFS: Dynamic Voltage/Frequency Scaling) technique.
In general, a CMP (Chip Multi Processor) includes a resource shared by a plurality of processor cores, e.g., a memory bus.
For this reason, the performance of a program executed by each processor core greatly depends on the properties of programs simultaneously executed by other processor cores. When a resource contention occurs, the performance of a program may greatly deteriorate.
The above conventional technique cope with this problem by only increasing the frequency/power supply voltage for a program whose performance has deteriorated, but do not perform any control in consideration of the influences of the resource contention with other programs. This may degrade energy efficiency.